This invention relates generally to electric cigar lighters of the type employed in automobiles or other motor vehicles, and more particularly to lighters of the type incorporating a socket part that is mounted on a dashboard or other panel, and a removable plug part that carries an electric heating element.
Many different constructions involving electric cigar lighters of the above type have been developed over the years. Generally, the socket of the lighter device had an out-turned flange or bezel at its front, and was inserted through a hole in the dashboard or panel, being held captive therein by a tubular clamping shell that was screwed onto the socket from the rear, behind the dashboard. The front edge of the clamping shell engaged the rear surface of the dash, and held the socket in position. That is, the dashboard or panel was sandwiched between the out-turned flange of the socket and the front edge of the clamping shell.
Most of the older model automobiles employed metal panels, and thus one part of the cigar lighter circuit was established from the metal part of the socket to the panel and ground. With the advent of newer car models involving both cost and weight reduction, plastic panels and different types of bezels are now being employed to a far greater extent. This generally necessitates the use of an additional grounding terminal or lug of some type, in electrical contact with the metal shell or body part of the socket. Previously, the electrical connection to this part was made by means of a spade lug that was welded to the clamping shell, and that was received in a cooperable grounding terminal from the vehicle electrical system. Since the clamping shell, being constituted of metal, was in electrical contact with the socket, there existed the required continuity for the ground circuit.
The clamping shell heretofore was formed from a deep-drawn metal blank requiring a number of draw operations and trimmings, and subsequent plating and finishing operations which added to the expense. On top of this, the welding of the connector lug constituted a complication in that the necessary subsequent plating and refinishing operations were time consuming and costly. A typical construction involving a drawn clamp shell is illustrated in U.S. Pat. No. 3,955,533 dated May 11, 1976, issued to F. J. Fellin, entitled CIGAR LIGHTER CLAMP SHELL, and having common ownership with the present application.
Several additional problems have also occured, however, with regard to the welding of a lug onto the clamping shell, the most important being the lack of a reliable and economical test for the integrity of the weld, and the sometimes frequent failure of the weld during the subsequent life of the component or shell.
Generally both the socket and shell were plated in order to avoid deterioration from moisture, particularly in cases where the lighters were to be mounted in the arm rests of the doors of a vehicle. Often the lighter would become wet if a window of the vehicle was inadvertently left open during a storm, or where the vehicle was exposed to a corrosive industrial or salt atmosphere.
In the past, when it was required to fasten an electrical connector in the form of a spade lug to the clamping shell, it had been customary to plate the parts after the fastening operation, since the welding disturbed any pre-existing plating. But, under any circumstance, the welding step was time consuming, involving manual labor, and this, as well as the plating of the finished parts, represented an additional expense. With the impact of the continually rising labor costs represented by the above, the clamping shell component of a cigar lighter started to become something that was cost-prohibitive and no longer economical to produce in the environment of lighters.